Optical filters are devices having wavelength-selective transmission acting on sources or receivers of light. Such filters may be configured to transform aspects of color appearance as seen by the human eye. Optical filters that improve or modify aspects of color vision may provide therapeutic benefit to persons with color vision deficiency, to persons with low-vision disorders and to persons with normal color vision. Optical filters may provide eye-protection from high-energy radiation in the ultra-violet, visible, and/or infrared spectra. Apparatus incorporating optical filters affecting color vision and/or color appearance include eyewear, contact lenses, scope assemblies, cameras, windows, coatings and lamp assemblies. Such apparatus may be generally referred to as optical systems. Apparatus wherein the optical filters act to modify light received by the eye using a lens or shield disposed in front of the face or eye are generally referred to as ophthalmic systems.